SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f754793248ac22408c6d4df9a65ee690d8adedf96724490f536e8479c181d986' 
  AND token = '1pnxEhOeRb1hcFW/WlV8bODYfFm1v+iTuu8o1TxRLZ0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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