SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b30398e78fbf1338de1df0a3c14d750d541c58d61e4eb859f6fb1857f18db439' 
  AND token = 'eULyxMxPRATgNnM6CEtPL7+vLCWrmdVeAdfs1UXEU3A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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