SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '594f562976141bc5d701497e7c4d9d6acc4a445331d6d449dd04b378cf24c7e0' 
  AND token = '/AiWkLW0pAysc89ZCnuimU9lCLzeGMKsy2kRdXDt2rI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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