SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cfb57b58ef80c8b15757b3d64e2bfd502eebf6296f05c7069b25363fef9cc213' 
  AND token = 'jjPFO+FyfrxwZ1aUUOFLYzrOn1+KjcL/Jzlf1WgbtzU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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