SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a76fb0aa94dfaa425fdda6f882d92e7e59ea4817e633bd492e4c94a3a5c1bafc' 
  AND token = '6T0Qios35eOhwRKBI92jalGvsYUKo7oR+jJbSpPzsV8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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