SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f485870e108697e356c8a4be6dee55a55768c2666943bd04f78b4475b5cfdd2d' 
  AND token = 'lWjgJVSXBaWrVQGZolJIVh8fAtbq3k5d+R6s2AOwX98=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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