SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ae319ceaab949d57c511b314cc6b1918f48ff9c8966dd7754c8d9b460bc84022' 
  AND token = 'xHmZ/eFZbDhwdl1ZrgdkgDSeY5TrSnejEJdaryONiMM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}