SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e918ce0f805f5333b303dcf213476a8fa7760b22457f696acb95c72f0f7ce44b' 
  AND token = 's+8Lmmnc4NS+g9RTdlxP0/DGVPAYXOP8wuEpiGFzsb4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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