SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fb8aa88b95b7681ff9ac8bc9a167d5fdc7ffe7d83650a0173191eeac7d50b207' 
  AND token = 'hq0CU/dNpRfUC2BRbA92aAZHO441JdHszAgCuWmWtyE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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