SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '777c355ef022100279d8e9944befec7a943656e9717ac4d3e14f007d86006bb5' 
  AND token = 'JjKtiEcJjcfNpJJ8IW8TAxgZKpEnx+wUphbDrW5XYmc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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