SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '464f936d258d648eab82775df801d087a97e2e8ee5d7aff4b1341dc3db7cf1e4' 
  AND token = 'i2NbcyM4LQnmuEE+YEsPQAwAU15nMBTP8X41kqdeTNk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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