SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '586ca433365cc5baabd204edf34b3fbafff30bfbab11e702427260118cccc162' 
  AND token = '+W3QamShnqH8d6PwJbW8/4U79a49CihbhTiQZy/T32g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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