SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '979e95dcef42149c4286345ad179dd40f6b9741c3018bbcc05e4836f622fd82e' 
  AND token = 'ObW/VHqY5kLLmstJN9yzgSuLj/iLuhzLCGO08JDOqkw=' 
  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"
    }
  }
}