SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6c7fa09deec92f16bf99cd44cb350204913667b785c780c7bf81d1ba2e87efd1' 
  AND token = 'R4gNg3ZKnYULBriDhAuSNrziTwpSHS+aV5dCghTBylk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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