SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd7c42fb2b880fe740410db38cd6dc3042bacc5afc7f98b3857b0c1b7708f77cb' 
  AND token = '6MmKOPBjzEqSXeJTMYMZkJxHLSAAakWFSWbqrXiU99k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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