SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3761381db4e1bf5e002433315c2a94349d77239afd0924ef2d97c4e14fcb2c8e' 
  AND token = 'CWD15QSeUIX1jhpGe5tWWLi89Uph6d95BTlHPsaOrTg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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