SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '53994fc6d5c6a017fca52cf02676fcb77b830498d9dd5cd5024df7edb759d3d1' 
  AND token = 'egr8hCFqlg6/u/S86pDGQsHvUVB7eWaSNWbtTnG1NCY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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