SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b4001d764198967ee78476395ea7108c711cdaee11ad48687549ba067c2a46f4' 
  AND token = 'Ql1ytmXFoDFbUAri1Vv6lJT0Q5vePyuNc8Sc7GQTkKs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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