SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '56c0fab91e08346dc5c2a130653ff9eeee4c197db7428f0b002dab4290f3496b' 
  AND token = 'j2g6LkBkKkFZVSUruCirLYXmb7E8vtda7yIBm4IxVgA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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