SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '647c112348fdda2d94e85d6881f47a307bce4b6fff9de032b118563342bd5f4f' 
  AND token = 'byrOhXIAsjtA3WHitukRJIrOr9Enn0JDXgcxfQea2l0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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