SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b2c5371ce4f6bc144b4e703d955fe1f8494713b7cde0d1846273d92d0e472262' 
  AND token = '4DfQSZsAQuf3RZkt8VvdTUwJaX77t5/Jn71yx/cughg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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