SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f8331641601cf5c35e89a51851e37fdb5896961f9e04bc50643b5c460e66af17' 
  AND token = 'uzkqUlqKYQY392eCnKiBtKT77niIZo4BopcK58w2lT8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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