SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5db2afdcfd1bb1b9efb8366605b04994e567d8265fd5142e8fde467759982d8a' 
  AND token = 'sx0812su+gSefkZWWyI9W/V1fi/V02Bo6xpnQDPw9Q8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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