SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2dd9d3ae01eba5051b1ce2fd2e78729b8b93b55312f9ed1988fdbeb608b44844' 
  AND token = 'UXq3NrWoVfm1Oe3bZOvm7DtZusBED8SF13bCUO1cLUE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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