SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '3e862f2b4ae9e8f61389b177dd45c1a1cd8665d9271e6999a5104b758f643d13' 
  AND token = '2TzMHYUrAXbXNzrJ5D4HUKALgxM5lvKr1ikt8KM61jc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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