SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bc7f1d6a519e5f174de86775b4976b8150a0a7a43fa427e0e30bf916070c1973' 
  AND token = 'EridEnjJSYlwqTcshcD96IQruKmKEpH+q1n5xBIcakg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}