SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '65140f48bda8754eaec19fe8e5927207189c043900b3184425a30a6a4408abac' 
  AND token = 'ACo/wqaUw0NIovGAtByMubmr3Z+g4yV5m8c6kNu5mU4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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