SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ab0df8ccf534bf00b925158f8418ee4870c4a94cad0c9cc66d9b0512fc3aedf9' 
  AND token = 'yaZjj5JgEwPXizNd1k8plwlavp9n1g5sjsy7JG2ZbyM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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