SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '453e08743ba0681708baf5bbe70d5f6c896ea0885073af599153f07317d9a8a4' 
  AND token = 'iXdlsdyGZFhbyrT0hTehdBr5XIBYOx0bgjAbc5vITtI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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