SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '44542ac8b846feeba472749b2fda5e2bea79ef70d0686c02caf37ffcac8eaa0b' 
  AND token = 'MM0TxVWzaitvkvhpsKj1gVzWSlLmClbqPTHJ+tOucbk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00053

JSON explain

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