SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f46b16ab4d917fe02130d58420647b944cb6ebfd700d60f014e3c56eeca55716' 
  AND token = 'Kgq1BaPdjEPO1dz9E+Blkhv+eCYSovQhlNXt+t5Xzb4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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