SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dad6d98c38a292e55d7fe1f7b4897bed3f05a55c6fcbd54ad5814a2a822335bc' 
  AND token = 'jUuQ/a0bmr/xY4oI8CZ2E3hz+vxMIRLPaxA+KsW7Yls=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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