SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '315908be58fe79074dcf3fb154e9c836454f8a69b2a951ef6f58408c8fcf3717' 
  AND token = 'mvPmfa+jjkBCTGy8u5sOcraCytoWAPoOSzdrOfwQhyY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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