SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3a0a77fc07286e6fea91be33405390367c58844a2b88db98cc4f42f65376bd0e' 
  AND token = 'fl03uCKfryuPwZhMxK/MqRgp0YJyQZ3AXL1GjrdfMMQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00053

JSON explain

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