SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '67dec84a3510c9afefbb8ec6ed3d4a0e53d42114888fc12867f0decf4a894ddd' 
  AND token = '06DN2fOdFHNa33TKThwRGVEByNcmkih5lLbFm+7JWv4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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