SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e8f150b4ca3c0a202d6745d55a06c42a3c1cf80a11906317f9ad54c85c3d2a2c' 
  AND token = 'V67Z0lMdoBR9kdOwD/U+hxjjYML6NDKlBEuZVpVxkmA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}