SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9daec90ca991672c0f619a9e79fd97788ac587bc6b471768b34613cf17bc373d' 
  AND token = 'ChMkN1f2YxOahMVAYLBgCQ/2zjy4iYx/IjK4+4PoOrQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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