SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fdbad7ab80c46604e8e7552ba2a14d373d0abd1777babaaf8c5f7b7d061b2da8' 
  AND token = 'zRrBIWZvcnJx/mKSHVgpuXN44iWYUxgwGYuzdUqSorQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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