SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5158026990b939c146d023241e71a537d40a9f326d9430ef0585890ec782f4ba' 
  AND token = 'rvLZEnhRCyrNrx/PfV4ZtjXDDYqgxKnra1PrBr3Guj0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00100

JSON explain

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