SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '88e608b778b626f597b5ab5bc6bda4515764420e2722fd6a3c259b1eca4a8471' 
  AND token = 'xkvdfMKmqNK7joQ25zWDtTXxyJdCUoLlNqvryzF1BOQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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