SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd626c50d575c13d244b4f062ccb00be877d7d2084a7dfe0fa4e7427abdffdbb1' 
  AND token = 'cu9ikAMqM2wNnVe8HN6pSoiMS4SJGbRaW/ohZlwBNSo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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