SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '2a45bff0a95959f76814944b31a875ac4297d479ce86329c1d62ad751b228732' 
  AND token = 'O3vhFHeVM6fGbwiL/icmo2neDKCu/NTGp2JWeXUlOsc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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