SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '10ae668246a5a3ebbb76fbb3379ce953a45806a3e59c13b2a8c90fc2ecaaaf4b' 
  AND token = 'SaMXEfZjOfePFCxQ8ykFMSnbBiw4VEJoLurqw7OI/Hg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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