SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'e07fe4fd3710e509c7255267bb0a7c71ff421f9b2d7d1954eddeeaa89e7ddc34' 
  AND token = '21bwqnf+CGbdDfikEC205aF+KhnoAbFH/Gv/gA1l0Fk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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