SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f54213e3a65c1cb6fa4acbd415ff68f37b639d3ebad06f87456ac8bde0f42835' 
  AND token = 'X8so0rEO/NQMpup/ebUsFloqm1pKSlWcL/YzR+/eHXI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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