SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '857b153e3b2e6122188f1e82e737cfb8a0bb07b61528355b74730527c4adae94' 
  AND token = 'XPCcW/69YVCmjTURMWHfBR39qgFbIAiWoMDVmkYfR7A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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