SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ee12d3eaa7f06f0fd779730d7a6d5b65947aeec22dfb5cba3a0c9f740dc46bcd' 
  AND token = 'zn//M7rfMlTOjttCP88GqYUiSUKL8uDreDfPjrtUyc0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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