SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4dc21dbd097f73892e9ab5834ed7410a6cc2ad801e31efd11e6ffcf7a649bf4a' 
  AND token = 'x6Ct6gN/jfV5l3RIUbfATd0M3kPsCdSSu4onPlmtC1k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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