SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6c066a62e3afa9dbf31a5f3ab5ee5f2e744a0e13e578b48dd6cb997ebff389f7' 
  AND token = 'j8ZOgbrvpeX1nsRkA5rrhWXMicCxD38ir7En1tIMACE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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