SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '6140e5d53dba187660b1f8a220a990365e29cedf28194bfa013a0f3dfeb11fd4' 
  AND token = 'YBGwvig0KuzpoaXHIFdvKSIpvuOH+6cUwYQjblgBBMo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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