SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e408325b1962e84f750ab81e4934aa290836330b84bc9375cbbd1accb1b90616' 
  AND token = 'rTGW6AcMtlz2oiuRIn8364JuciNWH3EUoAyY/98LpFk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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