SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c7fa3e5b00636b947d084f065e7dffb3d7cc111a1c1d503de01bbc2a15d71e5e' 
  AND token = 'xNOhUFoL+7UCjAKM5zH/B0IztK3yo/B99AIuxRRlN5Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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