SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '268ba140cb3ca81da19f159099358225b5777547982e226b3fa585b289ee9df2' 
  AND token = 'wc7skaH5xeMPKsG6x5k8l3o4E655jvnb1bny47zr9BA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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