SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '68963ef9273db06f66907bb33c5d4e5ec4431b0948b6c98b87cc396001e796f2' 
  AND token = 'eXp6uxOZj/4cF+UF/T330V0WyvmAGJz8LJjwEVJn3Iw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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