SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6ca563383540e8d0da4377f0fe0d53242542f0b0ea9e8fcbb4e82142f4cf4811' 
  AND token = 'GMUgpvmhiPsv7ndG1EpIU8DpyxSGrSk66RvqNVAY7Tc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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