SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6f877739094e1fd6809554499c883fdd90484fcc56bc6f046dcee53870de3ee0' 
  AND token = 'xpPk5nYOXmBDophW3iHjtDI6y6M5bUWFYVMRWVOfl/I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

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