SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '31d053ffb8b3482f2d0a1a9baa4362f1b71d2561e4a7e9159ee0863fc4e66d21' 
  AND token = 'f3mOQ8sgb0AoYvtJmU5ZlavoxwOj9/hs5HkNaR1VEwE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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