SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cb9eca07f849d0e115c5615d732af7bae926111dec34752f4669b717e121b2f2' 
  AND token = 'SAMRQoqupBH8EoeoJg30ytzLAR06t6IOCWLFKc+j2Xs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00056

JSON explain

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