SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '40e2d3030cef69b310fa557463320ea21592ac3ff683984e8db709972f4bf1c5' 
  AND token = 'aLHSJvX5ZqVY+6EMNfnKqjvfHlkDktufHReqk7wBO94=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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