SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '08176720fbb4e3dc347f7bc5313c2aab94642d62c4799c3b5934c72e3fa87eb3' 
  AND token = 'znYqtZFCT2uipBzKA0DVbthJT27z7q/x/fZtsxZtCFk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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