SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '510fb15d541832f56351dbca7b02859e5af09c2c5dd3be21b8a4a716ea31ad6f' 
  AND token = 'iT4L7yBAtDFc6p3ECE4uZHmN2pl8m0WfCbM2cwMCEYY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}