SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '74c03cbacf0fae5225a669f48270de0b250c1e2ba4b9dc64deafb2d8f0b470a4' 
  AND token = 'FiTBt9xBCHXJ8gRZtvZfCVyL07b4QoEO5TbovSIQK+4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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