SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '538497997d9bd30b8189d4e2c876c7bd87ae02ad7b0b1cf6188394eee4317a0b' 
  AND token = 'L8sL0ORBr5hzM+K6/Z2TXFZKDisHyP0g/laszQmJXnQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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