SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '054cef2f9872a2787037494c118ac7206559da49fa1d6f618b03d65662048aaf' 
  AND token = 'OvE/U0fPZi2tq9M+LoLBkh+90VwcKwEGmpPmoBGEo8U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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