SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ffcb047cea5912391dc16ed58a1513eac644055d042dd77468fa504d610355dd' 
  AND token = 'JO2q0SXqZ7i6CzWGsPbd0wiutNS0iH2eNULkDyMAYX0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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