SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a9e6547c29276b2fb16b781bae7b29e9db25e57c67049af879fea832ddffe285' 
  AND token = '0NMg2ULklNFCVRvu3CMlEo5ZS7iwNnV6+ffIIA7rrR8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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