SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f406e3817947dd360aacdca2a10ff603e50a9a97f73fbb224f6446ae65589925' 
  AND token = '3+6mqPmYgPdDzTJG186NqHb9o38dk9VDZm5y3b/8QEM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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