SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7a1950a42b4bd241cb63a35acdb02d1c4ad92b80da41f9d21a6a111caaa685c7' 
  AND token = 'mVFQ0eRFNd0lF7l/zhCmNaVfLnywZXTycoqrIgPxRgM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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