SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2e515b8e8bf259f42b38e889829c173017476248a5f3e3268590be1fcb37d2ed' 
  AND token = 'DvmtlJ+hMRG6QUQ0jYhQ9iVNvXznlJoz43bJ+RRaDgo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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