SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f916b2d8f274366e0932c39d828e2c9bd9ff93d70e28aa88a0d22ae7818275bb' 
  AND token = 'dZ6ANs/x3LVSmmNQpN/eMXoTL+ZMbXjUTb3zvxris3Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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