SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8100e0bb827fa3740ce7fbfd1571184752162aaba5a883a0c61fa450f7c813f7' 
  AND token = 'mcsEfLnjht1yqFsCNnJKHUXr0lgeKaqyBBE0B4CedK4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00054

JSON explain

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