SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e7bbe457b53025cf4bb053969b34f39d86c71984100f104348fcaf3476d4079e' 
  AND token = 'weYONaakL1baoTLAMjGD71oxIVvzrNgIkoA5cLMVYtU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00059

JSON explain

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