SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1348ae79dfcb59a75b828678fe651885b9902137328268c7a4e6589dcdf375d6' 
  AND token = 'GGv8MmLWWC1TzEGZLofsHRWaHsB7EE0QgfBiNmsS4RA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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