SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '55e11a38edc6c534866fc073d0eda8536c9dfc96f8d04c526835c37f17fa9912' 
  AND token = '6peetDIYLPOLBPCMef17hR7wBBg8XcKN6O5fkvh8VCw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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