SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b753ad30bebe0a59450d5d936dfd6817328e3baeba9a830bffcdd556e84f7117' 
  AND token = '/DGNC4QfGUf+Jh3gk0xLB1TQ3IjvWPkIJEWKQCz3GSg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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