SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd0c0356e1d6b7e4288d4cc16d6dafec07fc611e8dccfe1e8bd5428a254e80100' 
  AND token = 'nZgcZ5vBWgGxol3n+mU8PdGgo/z9hJMXQJ9fqjH/SiM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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