SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6aa319522515b5fd5d568d06146093b70fe996bb78041a00eba8185bb335ffba' 
  AND token = '8m+Gh2OrRxq3LzcrtWxYPTfy7XFSw4j5CU7WiaxPhz4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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