SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e242eeada200ec34e5bc6c7149d5ccf63e5ee029be72353e6e41eeff819d0491' 
  AND token = 'gEeOmoJGVkCuue5pQaDOdgAU0Nb6m97ModqLAtsoWCE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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